As a gold-colored ornamental component, heretofore it has been customary to use gold, a gold alloy, or gold-plated metal of various types from a color tone or corrosion resistance standpoint. However, each of gold, a gold alloy, and a gold-plated metal material has low hardness, and is thus susceptible to surface flaw or deformation upon contact with a hard substance.
Moreover, due to the increasing variety of customer's preferences, there arises a demand for gold colors having different hues. To solve the above-mentioned problem, as well as to meet such a customer's request, the applicant of the present application has proposed gold-colored ceramics of various types to date.
An example of ceramic products proposed by the applicants is ceramics for ornamental component which is made of a titanium nitride sintered body predominantly composed of titanium nitride, and contains nickel, niobium, chromium, and carbon, and in which the carbon is contained in an amount of greater than or equal to 0.5 mass % but less than or equal to 0.9 mass % (refer to Patent Literature 1).
Another example is ceramics for ornamental component which is made of a titanium nitride sintered body and contains nickel, niobium, chromium, and carbon, and in which the carbon is contained in an amount of greater than or equal to 1 mass % but less than or equal to 2 mass % (refer to Patent Literature 2).